sorry for the double post, but here it is right from Microsoft's webpage:
http://support.microsoft.com/kb/314865
If All you youngsters think you need a gig of RAM to simply function, then you've known nothing but Vista. Vista needs all that RAM for it's nifty Aero interface and because it likes to prefetch. LittleHaiti, you'll be fine. just free up some memory and do a scan.